Apparatus for forming and dimpling angular bends in rectangular tubing



A ril 12, 1960 F. J. FUCHS, JR.. ETAL 2,932,335

APPARATUS FOR FORMING AND DIMPLING ANGULAR BENDS IN RECTANGULAR TUBING 3 Sheets-Sheet 1 Filed Feb. 26, 1954 INVENTORS FRANCIS JFUCHS JR. 8 RALPH C. TAYLOR Owe ATTORNEY.

April 12, 1960 F. .1. FUCHS, JR. ETAL 2,932,335

APPARATUS FOR FORMING AND DIMPLING ANGULAR BENDS' IN RECTANGULAR TUBING Filed Feb. 26, 1954 3 Sheets-Sheet 2 INVENTORS FRANCIS J.FUCHSJR. 8 RALPH C.TAYLOR.

ATTORNEY April 12, 1960 F. J. FUCHS, JR. ET AL 2,932,335

APPARATUS FOR FORMING AND DIMPLING ANGULAR BENDS IN RECTANGULAR TUBING Filed Feb. 26, 1954 3 Sheets-Sheet 3 INVENTOR. =11 RANCIS J FUCHS JR 8 RALPH c. TAYLOR.

CL. dmma F 15. Q g

ATTORNEY United States Patent Q APPARATUS FOR FORMING AND DIMPLING AN- GULAR BENDS IN RECTANGULAR TUBING Francis J. Fuchs, Jr., and Ralph C. Taylor, Winston- Salem, N.C., assignors to Western Electric Company, Incorporated, New York, N.Y., a corporation of New York Application February 26, 1954, Serial No. 414,030

1 Claim. (Cl. 153-3) This invention relates broadly to apparatus for forming tubing, and more particularly to improved apparatus for simultaneously forming and dimpling angular bends in rectangular tubing.

It is frequently necessary in the fabrication of electrical assemblies utilizing wave guide tubing to effect angular bends in the wave guide tubing. It is desirable to maintain the interior dimensions of the tube uniform to prevent undesirable alteration of the electrical transmission characteristics of the tubing.

A first step in forming angular bends in such tubing comprises bending the tubing into a smooth, curvilinear form. A second step comprises inserting the curved tubing from the first step into a suitable die and performing a forming operation upon the tube to produce the final desired angular configuration.

It is also frequently required to alter the electrical transmission characteristics of wave guide tubing in a predetermined fashion such as, for example, producing concave-convex dimples or corrugations in the tube. In the past the production of such predetermined deformations of the wave guide tubing has been done in a separate step subsequent to the forming of the tubing.

Such forming and dimpling procedures and apparatus therefor are disclosed in co-pending application of Francis J. Fuchs, Jr., Serial Number 305,325, and now Patent No. 2,835,306, filed August 20, 1952.

It is an object of the present invention to provide an improved apparatus for operating upon a curvilinear section of rectangular tubing to produce an angular bend therein.

It is also an object of this invention to provide a tube forming apparatus whereby deformations of an accurately controlled character may be produced in a tube substantially simultaneously with the forming of the tube to an angular configuration.

Another object of the present invention is to provide an improved apparatus for maintaining the interior crosssection of a tube substantially uniform while the exterior of the tube is subjected to a forming operation.

In accordance with the above objects one embodiment of the present invention provides a tube forming apparatus including a base having a plurality of stationary die sections rigidly mounted thereon and forming therebetween a die cavity for the reception therein of a tube to be formed. A movable die section is reciprocably mounted upon the base and is provided with a plane forming surface having convex dimpling projections or punches thereon for angularly forming and simultaneously producing concave-convex dimples in one wall of the tube. An operating head is reciprocably mounted upon the base and has attached thereto a convex forming die for producing an angular configuration in another wall of the tube. A four-piece sectional mandrel is slidably insertable within the tube and is provided with a plurality of concavities complementary in location and configuration to the convex projections on the movable die section. Means are provided to actuate the operating head and the movable die section whereby the tube assumes an angular configuration and is also dimpled by being formed between the convex projections of the movable die section and the concavities of the sectional mandrel. A top plate is provided for attachment to the stationary die sections in order to hold the tube in place during the forming operation.

A second embodiment of the present invention provides an apparatus for performing an operation similar to that performed by the first embodiment and includes a base having a plurality of stationary die sections rigidly mounted thereon and forming therebetween an angular die cavity for the reception therein of a tube to be formed. A movable die section is reciprocably mounted upon the base and is'provided with a plane surface having a plurality of convex projections extending therefrom. An operating head is reciprocably mounted upon the base and has a convex forming die rigidly secured thereto. Two side-engaging mandrels are slidably insertable within the tubing and are provided at first extremities thereof with grooves and slidable sections mounted in the grooves. The mandrels and the slidable sections are provided with arcuate surfaces defining concavities corresponding to the location and configuration of the dimples which it is desired to produce in the tube. The slidable sections are adapted to move in the grooves relative to the mandrels to allow the mandrels to be withdrawn from the dimpled tube. Means are provided for actuating the operating head and the movable die section into engagement with the tube to form and dimple the tube. 1

Other novel features and advantages of the present invention will become apparent from an inspection of the following description when considered in conjunction with the accompanying drawings wherein:

Fig. 1 is a top plan view of the first embodiment of the invention showing a tube in place within the die cavity and the mandrel assembled within the tube prior to the actuation of the apparatus, the upper portion of the tube being removed for clarity;

Fig. 2 is a view similar to Fig. 1 after the actuation of the apparatus;

Fig. 3 is a perspective view of the top plate of the first embodiment of the invention;

Fig. 4 is a cross-sectional view taken on line 44 of Fig. 2, but with the top plate in position;

Fig. 5 is a perspective view of a tube prior to the forming operation by the first embodiment;

Fig. 6 is a perspective View showing the tube after the forming thereof with the sectional mandrel partially retracted from the tube;

Fig. 7 is a top plan view of the second embodiment of the invention showing a tube in place in the die cavity prior to the actuation of the apparatus, but with the upper portion of the tube removed;

Fig. 8 is a view similar to Fig. 7 after the actuation of the apparatus;

Fig. 9 is a fragmental top plan view of a portion of the mandrel showing the slidable section in position;

Fig. 10 is a cross-sectional view taken on line 10-10 of Fig. 9;

Fig. 11 is a perspective view of the tube prior to the forming and dimpling operations by the second embodiment, and

Fig. 12 is a perspective view of the tube after the forming and dimpling operations by the second embodi ment.

Attention is first directed to Figs. 1 and 5 which show a tube 15 prior to being subjected to the work operations performed by the first embodiment of the present invention. The tube 15, before being operated upon, is in the form of a smooth curvilinear section or elbow of rectangular tnbin'g'which has been'bent in*the'plane"of"its'" smaller dimension.

Fig. 1 also shows. the first embodimentof a tube formin'g anddimplinglapparatusiin an assembled position prior' 22 define a generally angularsdie cavity 24 for the recep-- tiorrthereini of" the tube to'be'formed. The stationary diefsections 18; 19, 21 and 22 further define passageways 27. The stationary dissections 18, 19, 21 and 22 are provided" with apertures or grooves 28 and stationary die sections18 and 19 are further provided with threaded apertures 29.

A forming'and dimpling die 31 comprises a movabledie' section and isprovided with a plane formingjface' 32 and convex'dimpling projections or punches 33 and 34 extending from the face 32.- The movable die'section 31 isreciprocably mounted upon the base 16 in'slidable'relationship with the stationary die sections 18 and 19 and forms; in'an'actuated position, a portion of the wall of the die cavity 24 for engagement with the right-hand wall (Fig: 1)' of "the tube 15 to be Worked upon; The movable diesectionfil is attached We shaft'36 to suitable actuaF ingmeans' such. as ahydraulically operated piston (not' shown).

Anoperatinghead 37 having a convex forming die" 38" mandrel sections 47, 48, 49 and 51 (Fig. 6), said mandrel sections having, in an assembled position a configuration substantially the same as the-finally desired shapeof'the tube.

Mandrel section 47, having substantially the sameconfiguration as a straight portion of'the tube 15, is slidably insertable into one extremity of the tube and has on one-extremity thereof a projecting tongue 52 and' on the other extremity thereof a shoulder 53 for engagement with the stationary die section 21.

The other extremity of the tube 15 is' filled with mandrel sections 47, 49 and 51. Mandrel section 48 is provided with an inclined plane surface 54 for supporting the interior of the left-hand wall of the tube opposite the planeaforming'surface' 46 of the convex forming die 38 and: with: a groove 56 for engagement with the tongue 52:0n2theimandrel section 47. Mandrelsection 48 is also provided with a concavity 57 complementary in configura tion;toi1theiconvex projection 33 and" opposed to the projection 33 When the mandrel sections are assembled within theztubez Mandrel section 48 is further provided with a shoulder SBJforJengagement with the stationary die section 22.

Mandrel section 49 is provided with an inclined plane surface 59for. supporting one portion of the interior of tlie;=right-hand wallof the tube oppositea portion of the plane forming surface 32 on the movable die section 31. Mandrelsection 49: is also provided'with a concavity 61 sitnilarxto:.the:concavity 57 on the mandrel section 48 and located opposite to the projection 34 when the man drel: sections are assembled within the tube. Mandrel section :49-is'further. providedwith an'ir'iclined cam surface 60. and With ashoulder 62 for engagement-with the stationary dietsection' 18.

Another mandrel section, denoted generally by the" numeral 51, censistsora' tapered or we'dge-lik'e portion 63 for insertion between mandrel sections 48 and 49 and a rectangular portion 64 for abutment with the shoulders 58 and 62 on the mandrel sections 48 and 49, respectively. The tapered portioni63 of the mandrel section 51 is provided with a plane inclined surface 66 for supporting another portion of the interior of theright-hand wall of In Fig. 3' is'shown a-top plat'e'71 adapted" to bemount ed upon the die block 17 in order tohold the positioned tube'lS in position during theforming operation. The top plate 71 is provided with a'pertures72' alignabl'e-with the apertures 29 m the' stationary die-sections 18 and 19 and' through 'which suitable connecting or clampingmeans (not'sh'ownYmayheinsertedf The" top plate 71 is also" provided with inserts or bosses-73havihg'; polished surfaces raisedabovetlie surfaceof o'ne sideof the' top' plate. Wlien'the top plate 71' is clampedabove the positioned tube 15 the-inserts 73 contact portions of'the tube 15 to hold-the tube rigidlyin position and to prevent scoring of the surface-thereof. The top plate 71' is further provided with indentations 74- for engagement with a plurality of positioning blocks 76 which'a'resecured to the stationary diesections' 18 and-'19 and which are adapted to accurately position the'top plate 71 relative to the die block 17;

With the ab'ove described apparatus and tube in the assembled positionthe-operating head 37 and the movable diesection 31?. are actuated into engagement with theleft-h'and and'therighthtmd walls, respectively, of

the tube thereby eifecting' in;- a single step an angular forming ofiboth thedeft-hand and=the right-hand walls of the tube and a dimpling of'the cornersin the right nand walLQFig: 2) ofithe formed tubein the shapcof concavo convex dimples or 'cor-ru-gations.

Upon. completion of; thefo'rming and dimpling operations, the top plate 71 is removed from the die block 17,

the. slides- 69' are removed fromi the grooves- 28, the

mandrel. section 41' iszremoved'from the tube 15, and the' taperedl mandrel section. 51' is then: removed fromthe tube thereby a towing mandrel sections 48- and 49 to be removed from around the: inwardly" projecting dimples: The. convex. formingidie 383 andi the movable die: section: 3-1 are theneretracted andethe: formed.- and dimpled. tube::may bearemovedl from thedie cavity 24.

Attention. is next. directed: to Figs;- 7 and: 11- which show' atube 166).: prion to being subjected tothe work operations-i performed: by; a second embodiment of the present-invention. Thedub'e 100, beforeibeing operatedupon isin the. form :ofa section: of rectangular tubing:

which 'has been bent in a smooth curve inthe-plane of its larger dimension:

Fig. 7- also illustratm-a second embodiment of a tube,

forming and dimpling apparatus inert-assembled position die sectionandis reciprocably m'ountedupon the base in slidable relationship with the stationary die'seetions 83 and 84 for engagement," iir anactuatedpositiozr, with the A die block is right-hand wall (Fig. 7) of the positioned tube 100. The movable die section 89 is attached at one extremity thereof by means of a shaft 91 to suitable actuating means such as a hydraulically operated piston (not shown). The other extremity of the movable die section 89 isprovided with a plane forming surface 92 and convex dimpling projections 93.

An operating head, designated generally by the numeral 94, is provided on one extremity thereof with a convex forming die 96 for engagement, in an actuated position, with the left-hand wall (Fig. 7) of the tube 100 to be worked upon. The operating head 94 is reciprocably mounted in a slideway 97 in the base 81 and is connected at the other extremity thereof by means of a rod 98 to suitable actuating means such as a hydraulically operated piston (not shown). Stationary die sections 83, 84, 86 and 87, together with the movable die section 89 and the convex forming die 96, define an angular die cavity 99 for supporting the external walls of the tube 100 to be formed.

The interior of the tube 100 is supported by two sideengaging compound mandrels designated generally by the numeral 101 and slidably mounted on the base 81 by means of retaining sleeves 105. The mandrels 101 comprise reciprocable arms 102, operating members 103, and arcuate cams 104. The reciprocable arms 102 are provided at first extremities thereof with T-shaped grooves 106 (Figs. 9 and in which are movably mounted slidable sections 107. The reciprocable arms 102 and their corresponding slidable sections 107 are provided with arcuate surfaces 108 and 109, respectively, which, in the assembled position of the slidable sections 107 in the grooves 106, define concavities 111 complementary g; the convex projections 93 on the movable die section The stationary die sections 83 and 84 are provided with threaded apertures 110 by means of which a top plate (not shown) may be attached to the die block 82, if desired, in order to restrain undue movement of the walls of the tube 100 during the forming operation.

In operation, a curvilinear section of tube 100 is placed in the angular die cavity 99 and the side-engaging mandrels 101 are partially inserted into the tube as shown in Fig. 7. The operating head 94 is then actuated to force the mandrels 101 into their final position within the tube as illustrated in Fig. 8, by acting upon the arms 103 in which position the convex forming die 96 engages the left-hand wall of the tube opposite to the arcuate cam members 104 to form an angular configuration in the left-hand wall of the tube as shown in Fig. 8.

A full understanding of the configuration and operation of the arcuate cams "104 may be obtained by reference to the aforementioned co-pending application wherein is disclosed an apparatus for producing seamless sharp bends in wave guide tubing, the second embodiment of the present invention being an improvement thereover.

Substantially simultaneously with the actuation of the operating head, the movable die section 89 is actuated into engagement with the right-hand wall of the tube whereby the right-hand wall of the tube is flattened between the reciprocable arms 102 and the plane forming surface 92 of the movable die section 89 and the corners of the right--hand wall of the angularly formed tube and are also dimpled in the shape of concave-convex corrugations between the concavities 111 in the reciprocable arms 102 and the convex projections 93 on the movable die section 89.

Upon completion of the above-described work operations a suitable retracting force is applied to the free extremities of the mandrels 101 whereupon the inwardly projecting dimples in the tube bear upon the arcuate surfaces 108 of the slidable sections 107 to move theslidable sections in the grooves 106 thereby allowing the mandrels 101 to be easily retracted from the tube.

It is to be understood that the illustrated embodiments are only illustrative of the present invention and that various modifications or additions may be made thereto without departing from the spirit and scope of the invention.

What is claimed is:

Apparatus for forming corrugations in prebent tubing which comprises a base having grooves formed therein, a plurality of stationary die sections rigidly secured to said base to form an angular die cavity for supporting the prebent tubing to be formed, a first mandrel slidably insertable within the angular die cavity and a first portion of the prebent tubing to be formed, the mandrel having a rectangular shoulder on a first extremity and an aperture near a second extremity, a sliding member received within a groove in the base and the aperture near the second extremity of the first mandrel for locking the first mandrel within the first portion of the prebent tubing, said first mandrel also having a concavity near its first extremity conforming in configuration and location to the corrugation desired to be formed in the prebent tubing, a second mandrel having a rectangular groove in a first extremity of sufiicient size to receive the rectangular shoulder formed on the first mandrel and an aperture near a second extremity, the second mandrel slidably insertable within the die cavity and a second portion of the prebent tubing to be formed, a sliding member received within a. groove in the base and the aperture near the second extremity of the second mandrel for locking the second mandrel within the second portion of the prebent tubing, said second mandrel also having a concavity near its first extremity conforming in configuration and location to the corrugation desired to be formed in the tubing, a first reciprocable forming die mounted on the base having a convex angular surface for angularly forming a first side of the prebent tube supported within said angular die cavity, a second reciprocable forming and corrugating die mounted on the base opposite said first reciprocable forming die, said second forming and corrugating die having a plurality of convex projections complementary in configuration and location to the concavities in the first and second mandrels so as to form corrugations in a second side of the prebent tubing opposite the first mentioned side of the prebent tubing when the second forming and corrugating die is advanced into the tubing, and means to reciprocate said first and second forming dies to simultaneously form and corrugate the prebent tubing.

References Cited in the file of this patent UNITED STATES PATENTS 50,753 Weimer Oct. 31, 1865 504,520 Davis Sept. 5, 1893 638,554 Burton Dec. 5, 1899 726,456 Prentice Apr. 28, 1903 1,239,177 Granz Sept. 4, 1917 1,322,116 Karns Nov. 18, 1919 1,423,586 Throne July 25, 1922 1,517,053 Fuller Nov. 25, 1924 1,923,272 Maroto Aug. 22, 1933 1,962,543 Wilson June 12, 1934 2,411,338 Roberts Nov. 19, 1946 2,512,849 Cork et a1 June 27, 1950 2,516,372 Cross July 25, 1950 2,832,393 Fuchs Apr. 29, 1958 2,835,306 Fuchs May 20, 1958 FOREIGN PATENTS 704,810 Germany Mar. 6, 1941 

